One aspect of the automobile that has changed little is the swing-out door. The swing-out door is suspended from the automobile body using conventional single-axis hinges. Each single-axis hinge comprises two leaves; a stationary leaf that is usually mounted on a forward portion of a doorjamb, and a hinge leaf that is usually mounted on a forward portion of a door edge. Each leaf comprises one or more knuckles which have coaxial through bores. The knuckles of two leaves are interleaved such that the through bores are placed in coaxial alignment. The leaves are rotatably joined together with a hinge pin extending through the bores.
The conventional single-axis hinge permits rotation within one plane. As the door is opened, the rear door edge swings out from the side of the automobile in a substantially horizontal plane, whereby a space for stepping-in and stepping-out is formed between the rear door edge and the automobile body. A major issue with swing-out doors is the situation of tight parking spaces with little room for the door to swing open to allow ingress and egress. Also, the potential for damage to an adjacent automobile is a persistent problem resulting in the inevitable door ding.
Other door opening configurations have been tried, such as sliding, gull wing, and vertical-lift doors. Sliding doors are popular on vans, but not automobiles. The single-axis hinges of the gull wing door are mounted along the upper door edge, the door forming a portion of the roof, and permits rotation of the door above the automobile; a design made famous by DeLorian Motor Company. The single-axis hinge of the vertical-lift door, which is also known as the lambo, scissors, or jack-knife door, is mounted in the forward upper door corner which permits door rotation substantially within a vertical plane defined by the door; a design made famous by Lamborghini.
The advantages of the vertical-lift door are both functional and aesthetic. Since the rotation of the door is upward and not sideways as with the common swing-out door, ingress and egress is greatly facilitated in closely-spaced parking situations. The vertical-lift door eliminates the potential of banging the door against an object located to the side of the automobile. The vertical-lift door also adds a sense of style and luxury to the automobile.
For the most part, vertical-lift doors have been available only on expensive luxury performance automobiles and automobiles assembled from a kit by the consumer. These vehicles have door and door jam configurations, single-axis hinges, and latching mechanisms specifically designed into the automobile to permit the door to open vertically.
Many automobile enthusiasts consider it highly desirable to incorporate exotic features into their ordinary stock automobiles. The vertical-lift door is one such feature that has for the most part been out of reach of the aftermarket enthusiast. Retrofitting the conventional door to operate as a vertical-lift door is difficult to impossible due in part to door and automobile body style. Many automobile body styles incorporate doors with contoured surfaces that would collide with the automobile body if opened as a vertical-lift door.
In some automobile body styles, the bottom edge of the door undercuts the automobile body and therefore would prevent vertical rotation of the door. Other automobile body styles incorporate roof structures that overhang the top edge of the door, precluding vertical rotation of the door.
These and other issues hinder the availability of aftermarket components that would permit the automobile enthusiast to retrofit the conventional swing-out door to operate as a vertical-lift door. These issues also hinder the automobile manufacturers from incorporating vertical-lift doors in automobiles without requiring major redesign of the current automobile body styles which may or may not be aesthetically pleasing to the customer.
It would, therefore, be highly desirable to have components and assemblies that would provide automobile manufacturers and aftermarket enthusiasts the ability to incorporate the motion of the vertical-lift door in currently designed automobiles without major modification to the automobile body or door structures.